3

Quad Capacitance

Capacitance of Schottky diode

quads is measured using an

HP4271 LCR meter. This

instrument effectively isolates

individual diode branches from

the others, allowing accurate

capacitance measurement of each

branch or each diode. The

conditions are: 20 mV R.M.S.

voltage at 1 MHz. Agilent defines

this measurement as “CM”, and it

is equivalent to the capacitance of

the diode by itself. The equivalent

diagonal and adjacent capaci-

tances can then be calculated by

the formulas given below.

In a quad, the diagonal capaci-

tance is the capacitance between

points A and B as shown in the

figure below. The diagonal

capacitance is calculated using

the following formula

C

C

C

C

C

A

B

C

The equivalent adjacent

capacitance is the capacitance

between points A and C in the

figure below. This capacitance is

calculated using the following

formula

1

C

1

1

1

–– + –– + ––

C

2

C

3

C

4

This information does not apply

to cross-over quad diodes.

SPICE Parameters

Parameter

Units

HSMS-282x

B

V

V15

C

J0

pF

0.7

E

G

eV

0.69

I

BV

A1E - 4

I

S

A

2.2E - 8

N

1.08

R

S

Ω

6.0

P

B

V

0.65

P

T

2

M

0.5

8.33 X 10

where

T = temperature,

°K

n = ideality factor (see table of SPICE parameters)

Note:

To effectively model the packaged HSMS-282x product,

please refer to Application Note AN1124.

Linear Equivalent Circuit Model

Diode Chip

ESD WARNING:

Handling Precautions Should Be Taken To Avoid Static Discharge.